1. Field of the Invention
This invention relates to heavy vehicle chocking systems, and more particularly to stowable adjustable chocking apparatus for use with flatbed carriers for effecting positive longitudinal and lateral chocking of heavy, oversize vehicles.
2. Description of the Prior Art
Many handling and securement problems are encountered when attempting to transport large, heavy wheeled or tracked vehicle equipment such as bulldozers, scrapers, graders, off-highway trucks, and tanks. Typically, these vehicles are transported on railroad flatcars or semi-trailer flatbeds. Because of the tremendous weights of such tracked or wheeled vehicles and the weight-associated problems encountered during their loading, a flatbed securement system preferably should be capable of being stowed at or below the level of the deck or be completely movable to an out-of-way position to protect its components. Alternately, if the securement system is permanently affixed above the carrier's deck, it must have sufficient strength to withstand the tremendous forces of the vehicle's grouser cleats or massive tires as they roll over it. Also, primarily because of ever increasing labor costs to both the shipper and carrier, it is desirable to have a heavy vehicle securement system for flatbed carriers of the type requiring a minimum amount of set-up and removal time.
Several devices are known for effecting either direct tie-down securement or block chocking of large wheeled or tracked vehicles. For purposes of the description herein, the term longitudinal shall mean aligned with the length of a flatbed carrier, and the term lateral shall mean transverse, or across the width, of a carrier. Also, the term track shall mean metallic grousers in an articulated series, while the term tread shall mean the ground-engaging periphery of a rubber tired vehicle. Some prior art chocking devices utilized restraining arms which provided direct longitudinal restraint to the vehicle axle. Anchorage of the deck-engaging ends of these restraining arms was effected in various ways, such as by being individually nailed to the carrier's wooden decking, or by threaded fastener or frictional connection to a longitudinally aligned track formed in the carrier's deck. Other known vehicle securement systems include non-stowable chocks which had a permanent curved configuration conforming to the vehicle's wheels; a common chock was the crudely-shaped wooden chock. Typically, these chocks were operable to be slid along tracks formed in the deck, and then fastened at the desired position by numerous fastening means. Still other known chocking devices included flat chocking plates capable of being raised from a flush-with-the-deck storage condition to the desired operating position, and then affixed to the flat bed via threaded fasteners. While one type of known vehicle chocking system combined individual movable chocks with chain or cable tie-down devices, still other systems used spring-urged, horizontally-extending arms to forcibly maintain the chock in the desired position. Devices of the prior art typifying the foregoing are illustrated in the following U.S. Letters Patent:
______________________________________ 1,699,290 1,816,897 1,733,269 2,034,893 1,776,935 3,752,086 ______________________________________
Because of the tremendous forces developed in heavy vehicles during their shipment, extreme securement forces are necessary to overcome vehicle movements such as swaying, cocking, and bouncing. Thus, any chocking system used must necessarily provide direct positive restraint to the heavy vehicle's tracks or wheels. Furthermore, because of the desirability of utilizing the least amount of labor possible during shipper handling of these vehicles, any adjustable chocking means must be quickly operable so as to allow expeditious loading and unloading. Since many heavy vehicles are oversize in comparison to the width of a normal flatbed carrier, and also of various overall shapes and sizes, it is desirable that any flatbed securement apparatus be adjustably operable to secure any heavy vehicle, regardless of the latter's width, length, tread dimensions, or even its tread type, such as metallic, resilient, etc.